Angiogenesis is a physiological phenomenon, in which a blood supply system is developed by formation of new vascular networks from pre-existing blood vessels. In angiogenesis, extravascular cells secret various signal factors to activate and mediate migration, growth, and proliferation of intravascular cells. These signal factors are called “angiogenic factors”, which not only promote the angiogenesis but also trigger repair of damaged blood vessels.
When requirement of blood vessels in tissues is due to hypoxia, secretion level of angiogenic factors increases so as to enhance opportunity of angiogenesis. Therefore, if a novel drug for angiogenesis promotion is developed, it can promote the blood stream of an affected region in a patient suffered from a certain disease, such as a cardiovascular disease, a myocardial infraction, or an ischemic disease. In such a manner, the affected region gains nutrients to recover the tissues and normalizes the ability to deliver blood and oxygen.